4 files changed, 44 insertions, 3 deletions
diff --git a/include/erebos/service.h b/include/erebos/service.h
index cec5ea0..ba06495 100644
--- a/include/erebos/service.h
+++ b/include/erebos/service.h
@@ -32,6 +32,8 @@ public:
 
 	virtual UUID uuid() const = 0;
 	virtual void handle(Context &) = 0;
+
+	virtual void serverStarted(const class Server &);
 };
 
 }
diff --git a/include/erebos/state.h b/include/erebos/state.h
index 543e03c..b1567b0 100644
--- a/include/erebos/state.h
+++ b/include/erebos/state.h
@@ -29,6 +29,9 @@ public:
 	template<class T> LocalState shared(const Storage & st, const T & x)
 	{ return updateShared(T::sharedTypeId, x.store(st)); }
 
+	vector<Ref> sharedRefs() const;
+	LocalState sharedRefAdd(const Ref &) const;
+
 private:
 	vector<Ref> lookupShared(UUID) const;
 	LocalState updateShared(UUID, const vector<Ref> &) const;
@@ -47,7 +50,7 @@ template<class T>
 LocalState LocalState::shared(const vector<Stored<T>> & v) const
 {
 	vector<Ref> refs;
-	for (const auto x : v)
+	for (const auto & x : v)
 		refs.push_back(x.ref());
 	return updateShared(T::sharedTypeId, refs);
 }
diff --git a/include/erebos/storage.h b/include/erebos/storage.h
index 75b8139..7ec73ab 100644
--- a/include/erebos/storage.h
+++ b/include/erebos/storage.h
@@ -507,12 +507,16 @@ class WatchedHead : public Head<T>
 	friend class Head<T>;
 	WatchedHead(const Head<T> & h, int watcherId):
 		Head<T>(h), watcherId(watcherId) {}
+	int watcherId;
+
+public:
 	WatchedHead(WatchedHead<T> && h):
 		Head<T>(h), watcherId(h.watcherId)
 	{ h.watcherId = -1; }
-	int watcherId;
 
-public:
+	WatchedHead<T> & operator=(WatchedHead<T> && h)
+	{ watcherId = h.watcherId; h.watcherId = -1; return *this; }
+
 	WatchedHead<T> & operator=(const Head<T> & h) {
 		if (Head<T>::id() != h.id())
 			throw std::runtime_error("WatchedHead ID mismatch");
diff --git a/include/erebos/sync.h b/include/erebos/sync.h
new file mode 100644
index 0000000..0b9ed9a
--- /dev/null
+++ b/include/erebos/sync.h
@@ -0,0 +1,32 @@
+#pragma once
+
+#include <erebos/service.h>
+#include <erebos/state.h>
+#include <erebos/storage.h>
+
+#include <optional>
+#include <mutex>
+
+namespace erebos {
+
+class SyncService : public Service
+{
+public:
+	SyncService();
+	virtual ~SyncService();
+
+	UUID uuid() const override;
+	void handle(Context &) override;
+
+	void serverStarted(const class Server &) override;
+
+private:
+	void peerWatcher(size_t, const class Peer *);
+	void localStateWatcher(const Head<LocalState> &);
+
+	const class Server * server;
+	std::mutex headMutex;
+	std::optional<WatchedHead<LocalState>> watchedHead;
+};
+
+}